Corona ignition devices are generally known from EP 1 515 594 A2, DE 20 2014 101 756 U1, and DE 10 2009 059 649, for example.
For corona ignition devices, the dielectric strength of the insulator is of great importance. Bypasses, flashovers and parasitic partial discharges can lead to premature failure of a corona ignition device. The risk of flashovers and parasitic partial discharges can be reduced with an electrically conductive coating of the insulator. Such coatings can consist of metal or electrically conductive ceramic and provide a cavity-free contact face between insulator and electric earth, which reduces susceptibility to flashovers and partial discharges. However, the end of the coating is susceptible to flashovers, since field peaks can form there.
To counteract this problem, it is known from DE 20 2014 101 756 U1 to provide an undercut in the insulator so that the tubular face of the coating is turned over its end. In this way, the end of the coating is situated in a field-free space, namely, inside a space provided by the undercut. In the radial direction the end of the coating is placed above an empty space provided by the undercut and above another section of the coating covering the bottom of the undercut. Therefore, flashovers can be prevented there. However, a disadvantage of this solution is the complicated shape of the insulator, which results in very high manufacturing costs.